Switch



SWITCH M. l.. JEFFREY July 29', 1952 Filed May 10, 1949 IN V EN TUR.

5 /QffOE/VE'Y BN QQ July 29, 1952 Ml L, JEFFREY 2,605,373

SWITCH Filed May 10l 1949 2 SHEETS- SHEET 2 F 4. 4l/lili.-

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BY MAX .JffFREY A//S 770,2/VE Y Patented July 29, 1952 SWITCHv Max L. Jeffrey, Hunting Valley,l Ohio, assignor to The National Acme Company, Cleveland,

Ohio

Application May 10, 1949, Serial No. 92,295

(Cl. 20G-159) 8 Claims. l

This invention relates to electrical switches and more particularly to a switch havingl an improved type of movable contact used to complete the circuit.

Since the completion of an electric circuit or its interruption is usually a matter of4 bridging or opening a gap between the endsr ofv a pair of conductors, a multitude of devices havey been found which will accomplish the desired result. Nearly all of these devices have a common fault in that when a circuit carrying a moderate or large load is broken, a severe are is formed at the contacts which causes burning at the contact points. This burning causes failure of the contacts after a certain limited number of make and break cycles. My invention reduces the severity of the arc, as has been shown by laboratory tests, and also provides a yieldable mounting of the contacts which allows them to move somewhat to adjust themselves to the position where they will make the best contacts and, therefore, cause the least power loss in the switch. Furthermore, the contact is such thatthe actual' contacts are moved so that they take different positions upon sequential operations presenting new surfaces and thus lengthening the life. Because of the con.- struction, the device offers a greater amount of contact; surface overA a period of time.

Other advantages and the invention itself will be made apparent by referring t the following figures and description which forms a part of this specification.

In the drawings:

Fig. 1 is aside elevational view of an embodiment of my invention in a double pole single throw switch with a part of the housing broken away to show the stationary contacts;

Fig. 2 is an end view of one end of the switch;

Fig. 3 is an end view of the opposite end thereof; A

Fig. 4 is a sectional view along line 4--4 of the switch of Fig. 2 modified to include an oil seal ring;

Fig. 5 is a sectional view Fig. 2;

Fig. 6 is a sectional view along line 6 6 of Fig. 1;

Fig. '7 is a sectional view along line 1 1 of Fig 1;

Fig. 8 is a View of a short stationary contact removed from the switch housing;

Fig. 9 is a similar view of a long stationary contact.

Fig. 10 is a View of one type of movable contact for use in my invention;

along line- 5--5 of Fig. 11 is a View of an. alternative form of movable contact;

Fig. 12 is a view of a second alternative form of movable contact;

Fig. 13 is a view showing my invention as adapted' t0 a single pole `double throw switch;

Fig. 14 is a view of a modification of the switch of Fig. 13l with the push button in cross section to show a method of sealing the switch from external oi-l;

Fig. 15 is a view of the swtchsimilar to that of Fig. 1 showing an alternative type of oil sealing;

Fig. 16 is a end View of an alternative form of my invention with the end cover removed;

Fig. 17 is a sectional View along line I'l-Il of Fig. 16;y

Fig. 18 is a sectional endk View of another alternative form of my invention; and

Fig. 19v is a view 0f the movable Contact used in the embodiment shown in Fig. 18.

Briefly, my invention comprises a switch, which may be of a push button type, but my invention, while chiefly described i-n such an embodiment, is not t0 be limited thereto. The switch is formed of a multiple piece housing having stationary contacts iixed therein with provision made to connect these contacts t0 the electrical power line in which the switch` is to be used. A carrier member controlled by the push button or rotary device is movably disposed in the housing and carries the improved type movable contact member which is floatingly mounted in the carrier, being restrained endwise only by the walls of the housing. The movable contact may partake of any of a number of forms including the illustrated cross Ibar whose end portions are adapted to make the contact with the stationary contact members. ,Surrounding the bar is a coil spring which engages the slide member and forms a yielding mount and additionally carries some current and has certain arc reducing effects hereafter described. y

My invention will now be described with more particularity, and with reference to the drawings throughout which like parts are referred t0 by like reference characters. The switch housing for the push button type switch, as best shown in Figs.` l, 4 and 5, may be formed of a plurality of parts; in this case three, a top part I l in which the push button l2 operates, a center or body part i3 and a base part I4. These parts may be held together by screws l5. extending through the parts and threadably engaging threaded bushings IB pressed into the top part Il. The heads ll of the screws l may preferably be embedded in the base piece I4 by counterboring holes I8 therein and lling them with sealing wax, after the screws are in place.

The stationary contacts may be formed in two pieces, including posts I9 and I9 each having a plate 2Gv which are secured together as shown in Figs. 8 and 9. Each post has a hole 22 which is threaded to receive a screw 23. The screw is inserted through electrical connectors 24 which may be soldered to the wires of the circuit and then threaded into the post, thus making the required electrical contacts. It will be obvious that the posts I9' of these contacts may be of varying length dependent on their position in the switch housing or the thickness of the parts of the switch, etc. In the double pole single throw switch shown in Figs. 1-7, there are two contacts with long posts I9, for the top contacts and two with shorter posts for the lower contacts. It will also be obvious that the angle of the plate 20 with the post I9 may be reversed as shown in the single-pole double throw switch in Fig. 13. These contacts are inserted into sockets formed for them in the housing parts of the switch and are prevented from coming out of their sockets by another part of the housing being fastened over them. The screw 23 when inserted serves as an additional holding means for these contacts.

A slide member 26 extends into the housing of the switch and is slidably journalled at one end 2l in a slot formed in the base I4 and at the other end by a rod 28 which also comprises an operating stem extending through an opening in the tcp II. Movable contacts 29 are carried by this slide member toward or away from the plates 20 of the xed contacts to make or break the circuit.

The movable contact may be made in any of several forms as shown in Figs. -12 and 19. Each embodiment, however, has a coil forming a part of the electrical current carrying circuit. This provides a spring-like mounting for the contact and has an apparent electrical effect which has been proved by laboratory tests. For reasons not fully understood by me, this type of construction appears to inhibit the arcing over of the switch when the circuit is opened. This result has been proved, not only by oscillograph tests of the circuit, but also by endurance tests which showed that after 1,200,000 separate closings and openings of a circuit carrying ten amperes of current, the contacts were still in very usable condition.

The movable contacts as shown in Fig. 10 comprises a cross bar 29 which carries a pair of contact members 30 in the form of cylinders at each end of the bar. A spring 3l surrounds the bar and is wound in conical form tapering outward from each end toward the middle 32. In the assembled switch, the slide member 26 engages the larger middle convolutions 32 of the spring and thus the slide may be deflected to somewhat greater extent than can the contacts. As a result, the movable contact is allowed some movement and will seat so that there is equal pressure on each of the two contact members 30. This equalization of pressure assures that variations in the formation of the stationary contacts 2U will not result in a heavy pressure and good contact on one side and light pressure and poor or no contact on the other. Thus, the new construction provides uniformly good contact on the two contact plates 2S contacted at any one time. The contact is held in place on the slide by the side walls 33 and of the housing as best shown in Fig. 5.

Alternate forms of the movable contacts are shown in Figs. 11, 12 and 19. The rst of these shows a form similar to that of Fig. l0 having a central bar 35 of concave shape having a uniform diameter for the convolutions of the spring 36 disposed thereabout. End plates 3l hold the spring in position on the bar. The end contacts are formed of silver sleeves 39 fastened onto studs 40 extending from the bar.

The second alternative form dispenses with a central bar and relies for its whole rigidity and strength on a coil 4l the convolutions being formed from a flat strip of electrical conducting material such as phosphor bronze. The ends 42 may be brazed or welded to this coil and may be either the solid ends of the rst embodiment or the silver coated ones as described under the rst alternative.

The third alternative as best shown in Fig. 19 is similar to the original embodiment except that the spring is formed with two enlarged portions 32 and 32". The contact may then be supported at two points, thus preventing tilting of the contact in its carrier except on contact with a firm surface. This is particularly useful in the ernbodiment of my invention shown in Fig. 18 and described hereinafter.

As stated above, one end o the slide member 26 is in the form of a rod 28 extending through the top piece. Several methods of forming an oilproof seal for this member are shown. In each case, however, a coil compression spring 64 is disposed about the rod 28 and engages the top member Il and a push button I?. which is fastened to its rod 23 by a pin 46. In the coniiguration shown in Figs. 1 to 7, the top I I is formed with a hollow 4l having a central boss d8. The rod 28 extends through the boss 48, and the spring 44 surrounds the boss and is positioned thereby. Oil sealing is accomplished by use o an external gasket 40 of rubber or other i'iexible material having upturned edges 5i) about the push button I2 which serve to wipe off the push button every time it is pushed, therefore preventing the leakage of oil into the housing. Alternative oil seals are illustrated in Figs. 14 and 15 where use is made of a housing top part II having a hollow 52 similar to the hollow 47 above but lacking the central boss 48. In the rst of these, a narrow rubber ring 53 is held in place embracing the rod 28 by a washer 54. In the second, the whole washer 55 is made of rubber having an upturned lip 56 embracing the rod 28 and is held in position by the spring 44 alone.

The single-pole double throw switch shown in Figs. 13 and 14 is made up of a top part Il and a base part I4 in which are disposed the stationary contacts having plates 28 bent at opposite angles. A shortened slide member 5S with a rod 28 for attaching the push button I2 is journalled at its end 59 similarly to the longer slide 25 used in the two pole switch previously described. In all other respects, this switch is similar to the previously described embodiment.

The operation of the push button switch is evident from the gures. The push button I2 is depresesd to close the circuits in the two pole switch. As it is depressed, the slide member 26 carries the contact ends 3Q into contact with the plates 20 and the movable contact member seeks a position where the pressure on each engl is the same resulting in the best possible contact. This completes the circuits and the current flows from one plate through the movable contact member bar and the coil to the connected plate. Upon breaking the circuit, both contacts are broken simultaneously as a result of my construction and this may have some effect on the arcing of the contacts. The operation of the single pole double throw switch is similar except that there is no stable of" position. Either one or the other of the circuits is connected. It should also be noted, particularly in connection with Figs. i0, 11 and 19, that the contacts being cylindrical may roll on the fixed contacts. Thus the point of contact is always at a different point around the cylinder with the result that the deterioration due to arcing is not concentrated in any one point for successive breaks of the circuit under control.

A rotary switch utilizing similar movable contacts is shown in Figs. 16v and 17. In this embodiment, the fixed contacts are mounted in the housing 60 in the usual manner in a proper position to be engaged by the movable contact ends 30. A cylindricaI contact carrying member 6I having ears G2 is rotatably journalled in the housing 60. A tongue 63 may be provided on one end of the carrier El to adapt it to be driven by a knob or handle means or a snap action mechanism not shown. A groove 65 may be formed on the other end of the carrier for the attachment of additional units if desired. Holes 66 are formed through the ears 62 to receive the movable contacts. These holes are suihciently large that the center portion 32 of the spring 3| will be freely disposed therein. The walls 61 and B8 of the housing serve to prevent the movable contacts from moving endwise out of position.

A second type of rotary switch embodiment of my invention is shown in Fig. 18. bodiment the type of Contact shown in Fig. 19 is preferred, since the forces on the contact members 30 are in opposite directions at opposite ends. Use of the first type of contact would result either in a simple turning of the floating contact freely about its center, or if the other two alternatives were used, a less effective contact because of the lack of resilience of the spring near the ends. In this embodiment, the contact is floatingly carried in a hole 10 in the rotary carrier member H which is journalled in the housing 12. Fixed contacts 13 are provided in the housing in position to be engaged by the contact ends 30. The ends of the carrier member may well be formed similarly to the embodiment of Fig. 16 to allow use of the switch in multiple units or to provide a snap action mechanism therefor.

It is apparent that I have provideda switch wherein the moving contact member is fully floatingly mounted,`and that this results in more effective operation of the switch.

Having thus described my invention, I am aware that numerous and extensive departures may be therefrom without departing from the spirit or scope of my invention.

I claim:

1. In an electrical switch having fixed contacts, movable contact means for completing the elec- In this emtrical circuit between said fixed contacts comprising cylindrical end portions for engaging said fixed contacts, bar means extending between said end portions and a coil spring surrounding said bar means for springably mounting said movable contact means in said switch.

2. In an electrical switch having iixed contacts, movable contact means for completing the electrical circuit between said Fixed contacts comprising end contacts for engaging said fixed contacts, bar means extending between said end contacts and a coil spring surrounding said bar means for springably mounting said movable contact means in said switch.

3. An electrical switch as set forth in claim 2 wherein the coil spring has small convolutions engaging the bar and larger convolutions intermediate the smaller convolutions, said movable contact means being mounted by said larger convolutions.

4. An electrical switch as set forth in claim 2 wherein the bar means is larger adjacent the contacts and smaller in its intermediate portion.

5. An electrical switch as set forth in claim 2 wherein the coil spring is provided with small convolutions engaging the bar adjacent the contacts and larger convolutions are provided spacedy from each other and the smaller convolutions.

6. A switch as provided in claim 1 wherein the movable contact means includes a carrier member slidably journalled in the housing.

7. A switch as provided in claim 6 where the carrier member is formed with a hole therethrough and the spring member has the larger convolutions in engagement with the wall of the hole.

8. In an electrical switch, a housing, fixed contacts disposed in the housing, a movable contact carrier rotatably journalled in the housing, movable contact means for` completing an electrical circuit between the iixed contacts comprising cylindrical end contacts for engagement with the fixed contacts, bar means extending between said end contacts and a coil spring surrounding said bar means for springably mounting said movable contact means in said rotatable carrier.

MAX L. JEFFREY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,453,587 Hertzberg May 1, 1923 2,201,881 Bryant et al- May 2l, 1940 2,202,207 Johnson May 28, 1940 2,355,951 Coifeen et al Aug 15, 1944 FOREIGN PATENTS Number Country Date 382,260 Great Britain Oct. 20, 1932 

